Analysis of phytoplankton community structure characteristics of Suzhou Taihu Lake Wetland Park

This paper is to present the results about phytoplankton community structure in Suzhou Taihu Lake Wetland Park,in hoping to explore the purification effect of the constructed wetland on phytoplankton community structure. As is known,phytoplankton plays an important role in aquatic ecosystem and constitutes part of the biological productivity and food chain in water bodies. Since the phytoplankton species vary due to the different water environments and growing conditions,the composition of phytoplankton can also be an excellent indication of a given water environment. Take phytoplankton from Suzhou Taihu Lake Wetland Park for example. We had done our investigations in April 2010,August 2010,November 2010,respectively,and made our analysis with the phytoplankton species,biomass and dominant species. The results of our investigation and analysis include:( 1) There has been found a total of 80 phytoplankton species of 46 genera of 7 divisions with 53. 8% of the identified phytoplankton species belonging to Chlorophyta( 43 species,23 genera),23. 8% to Bacillariophyta( 19 species,13 genera),and 12. 5% to Cyanophyta( 10 species, 5 genera),and Euglenophyta of 3. 8%( 3 species,1 genera), Chrysophyta of 2. 5%( 2 species,2 genera),Cryptophyta of 2. 5%( 2 species,1 genera),and Dinophyta of 1. 3%( 1 species,1 genera).( 2) The maximum biomass( wet weight) of phytoplankton was in April( 17. 84 mg / L),minimum biomass( wet weight) of phytoplankton was in August( 2 mg / L). The average biomass of phytoplankton was 9. 45 mg / L,the greatest percentage, that is,71. 05% was Bacillariophyta( 7. 02 mg / L); Cyanophyta only accounted for 1. 83%( 0. 06 mg / L).( 3) The dominance analysis proves that there are eight dominant species,including Chroococcus minutes,Merismopedia minima,Melosira granulata, Cyclotella sp.,Synedra acus,Navicula sp.,Cosmarium sp., Chromulina sp.,among which,Melosira granulata stands at the highest position( 0. 2),followed successively by Merismopedia minima( 0. 13),but the biomass of blue-green algae in the park was lower than that of outside,which demonstrate the wetland system may have an inhibitory effect on the blue-green algae.( 4) From the analysis of the species composition and biomass,it can be found that the community structure of phytoplankton tends to have a temporal variation and spatial variation because of the diverse ecological environment.